I've had two issues with my F-350 2002. One, alt went out. Easy replace. Week later wont start. Bad alt / batteries went at same time. Maybe coincidence maybe poor alt for a long time killed batteries. Put in two new Costco batteries. Year later, batteries dead. Took back to Costco and they gave me two brand new batteries now questions asked. Two weeks later, alt goes out😊 lifetime warrantyat Napa get a new one. Week later alt goes out again. Napa, get a new one. At this point, I can change an alternator on an f 350 psd in 7 minutes in the Napa parking lot. Another week later that one goes tits up. That was in 2010 I think. Not a problem with batteries or alt since then.
